The present invention relates to novel S-nitrosothiols derivatives of penicillamine or glutathione having vasodilating effect and which inhibit the aggregation of the platelets and which therefore are useful for the preparation of medicaments for treatment of dysfunctions of the circulatory system, specially at cardiovascular level.
It is well known that compounds capable of releasing nitrogen oxide (NO) into the organism exhibit in many cases some type of activity of the vascular system, for example vasodilating activity or inhibition of the aggregation of the platelets, which make them potentially useful for the treatment of different disorders related to dysfunctions of the circulatory system.
Further, it is described too that specific derivatives which contain a S-nitrosothiol group have, from a medical point of view, advantageous characteristic due to that they are capable of releasing NO in the organism.
Radomski et al., Br. J. Pharmacol. (1992) 107, 745-749, describes that the S-nitrosoglutathione (GSNO) compound are capable of inhibiting the activity of the platelets.
Golino et al, Circulation Research, 71, No 6 (1992), describes that S-nitrosocysteine is capable of inhibiting the activity of the platelets, due to an effect of anti-thrombosis.
Smith et al., Met. Find. Exp. Cline. Pharmacy. (1994), 16, 5, describes that the GSNO produces a strong relaxing effect of the arterioles.
WO95/12394 describes the use of S-nitroso adducts of peptides, among others the S-nitroso-N-acetylpenicillamine (SNAP), as protecting agents against vascular inflammation of traumatic origin.
WO95/07691 describes the use of different S-nitrosothiols, in particular the GSNO, in the treatment and prevention of the action of the platelets and the formation of thrombosis at the damaged vascular surface.
WO93/09806 describes S-nitrosated proteins or amino acid residues, capable of releasing NO, which have a relaxing effect on the musculature and an inhibitory effect on platelet aggregation.
EP-B1-412699 describes S-nitrosothiols which correspond to following general formula: 
and its use as therapeutic agents against cardiovascular diseases, in particular as anti-hypertension (increased blood pressure) and as agents for the treatment of angina pectoris. The number of possible compounds within said formula is enormous and the description only explicitly describes several tens of such products. Further, there is only disclosed data concerning their general vasodilating effect, and nothing is mentioned in relation to the activity on the platelets.
The S-nitrosothiols described by the documents mentioned above do not by itself solve all the complicated problems within the treatment of vascular disorders, specially at cardiovascular level. It is therefore necessary to develop new compounds which are more potent and effective.
An object of the present invention relates to novel S-nitrosothiols derivatives of penicillamine or glutathione, which both have a potent vasodilating effect and a high inhibitory effect on the aggregation of the platelets.
Further, an object of the present invention relates to the use of the novel compounds for the manufacture of medicaments for the treatment of disorders related to dysfunctions of the circulatory system, specially at cardiovascular level.
The compounds of the invention are S-nitrosothiols derivatives of penicillamine or glutathione, and its pharmaceutically acceptable salts, which correspond to following general formula(I) 
in which:
A and B are phenyl groups or together form the rest xe2x80x94CH2xe2x80x94Qxe2x80x94CH2xe2x80x94 constituting a ring of six units in which Q represents an atom of oxygen, of sulfur, or a group N-R3, in which R3 is hydrogen or an alkyl group C1-C4;
R1 is an acyl rest, which may be an aliphatic acyl group C1-C5 or a rest of glutamic acid bound via its non amino acid carboxyl;
R2 is a hydroxyl group or a glycine rest bound via a peptide bond;
with the proviso that if R1 is an aliphatic acyl rest then R2 is a hydroxyl group, and if R1 is a rest of glutamic acid then R2 is a glycine rest
Consequently, the compounds of the invention correspond to following general formulas (II) or (III) 
in which A and B have the meanings mentioned above and R4 is an alkyl group C1-C4, or a pharmaceutical acceptable salt of this.
Preferred examples of compounds within the object of the invention are following: N-acetyl-2-amino-2-[4-(4-S-nitrosomercaptotetrahydro-pyran-pyran) ] acetic acid (1). 
For the skilled person it is obvious that the compounds of the invention comprise chiral centers and this permits to distinguish between the possible isomers and/or the mixtures of these. It should be understood that both the mixtures of isomers and the pure isomers are within the object of the invention. The latter may be obtained from the mixtures of isomers through conventional techniques well known to the expert or through asymmetrically synthesis also well known to him.
The compounds of the invention may be obtained in different manners and the specific manner will generally depends of its basic structure.
For example, the compounds of the general formula (II) may be obtained according to the sequence of steps illustrated in the following scheme. 
I.e., starting from the chlorhydrates of the amino acids, which may be obtained according to known methods (see e.g. DE-A-3023830 and DE-A-2801849), followed by an acylation of the amino acid nitrogen group through conventional techniques, for example by an acid chloride, and in an final step is then introduced a nitroso group at the mercaptanic sulphur, also by use of conventional techniques.
In relation to the compounds of the general formula (III), they may be obtained according to the sequence of steps illustrated in the following scheme. 
I.e., starting from the same chlorhydrates of the amino acids as in the case above, followed by a protection of the mercapto group through the formation of a thioether of p-methylbenzyl. This is followed by a protection of the amino acid nitrogen through the known technique of Boc and thereafter is formed the tripeptide with the rests Glutamic acid and Glycine (amino acid C-terminal) in solid phase through known techniques (see e.g. Barany, G. et al., The Peptides, 2,1, Gross, E. Meienhofer, Eds.Academic Press, NY (1980); Stewart, J. M. et al., Solid Phase Peptide Synthesis, Freeman, San Francisco, Calif. (1969); Bodanszky, M. Et al., Peptide Synthesis, 2nd ed., Wiley, N.Y. (1976)).
The formation of the tripeptide comprises following steps:
a) Anchoring the amino acid C-terminal Glycine (Gly), in form of a tert-butoxycarbonyl (Boc) derivative, at a resin of p-methylbenzylhydrylamine/polystyrene.
b) Removing the Boc group with trifluoroacetic acid and neutralization.
c) Incorporating the intermediate protected modified amino acid.
d) Evaluating the coupling reaction via ninhydrin (Kaiser, E. et al., Anal. Biochem., 34, 595 (1970)).
e) Repeating the steps above for the residue xcex3-Glutamic acid (xcex3-Glu) which is incorporated as a Boc-derivative or benzyl protected (Boc-Glu-OBzl).
f) Acidolysis with anhydrous HF to unprotect the tripeptide and release it from the resin.
g) Purification and characterization of the final products.
Once the tripeptide is formed there is proceeded, as a final step, to the nitrosation of the mercapto group released from its protecting group.
The tests performed demonstrate that the novel S-nitrosated compounds of the invention have a vasodilating activity which is, at least, comparable to that of the GSNO, and in some cases highly superior. Further, they have an inhibitory effect on the aggregation of the platelets which also results to be similar or superior as compared to the GSNO, in some cases considerably superior.
This results in that the compounds of the invention may be used in a very efficient manner for the manufacture of a medicament with vasodilating and anti-thrombotic effect for the treatment of dysfunctions of the circulatory system, specially at cardiovascular and coronary level.
Consequently, the compounds of the general formula (I), as well as the pharmaceutically acceptable salts of these, may be used, via the use of conventional pharmaceutical techniques, for the preparation of medicaments which may be administered in different manners.
As an example they may be administrated orally in the form of pharmaceutical preparations such as tablets capsules, syrups and suspensions. Parenterally in forms such as in solutions or emulsions, etc. They may also be administrated topically in form of creams, pomades, balsams, etc., and transdermically for example through the use of patches or bandages. They may also be applied directly in the rectum as suppositories. The preparations may comprise physiologically acceptable carriers, excipients, activators, chelating agents, stabilisators, etc. In case of injections there may be incorporated as physiologically acceptable buffers, solubilizing agents or isotonics. The daily dose may be varied depending on the specific symptoms, the age, the body weight of the patients, the specific mode of administration, etc., and a daily normal dose for an adult person could be between 0,1 to 500 mg, and could be administrated as one dose only or divided into several doses during the day.
In the working examples herein (vide infra) are described in details suitable processes to obtain various of the compounds according to the general formula (I). In view of these examples, it is within the skilled persons general knowledge to obtain the compounds not explicitly exemplified herein, via suitable modifications the of working examples herein.
Consequently, the working examples herein should not be interpreted as limiting the scope of the invention, but solely as an additional detailed explication, which guides the skilled person to a more deeply understanding of the invention.